Numerous means have been sought to improve the fuel-efficiency of moving bodies and, especially, moving bluff bodies by reducing their aerodynamic drag. In the field of surface transportation and, particularly in the long-haul trucking industry, even small improvements in fuel efficiency can reduce annual operating costs significantly. It is therefore advantageous in the design of a vehicle to reduce drag forces, thereby increasing the aerodynamic properties and efficiency of the vehicle.
Most large long-haul tractors exhibit less than optimal aerodynamic performance during highway operation. At highway speeds, these conventional vehicles develop a substantial amount of turbulent airflow in and around various locations of the vehicle. One such location is the wheel openings define between the fender well and the tires. This area allows airflow, and especially cross flow, to impinge upon interior surfaces of the vehicle, thereby producing turbulent flow. This turbulence results in significant aerodynamic drag, increasing both fuel consumption and Nitrogen Oxide (NOx) emissions of the tractor.